1. Field of the Invention
The present invention relates to a synchromesh type automatic transmission of a vehicle such as an automobile and, more particularly, to a method of controlling a shifting operation of the automatic transmission which can prevent the driver of the vehicle from feeling such an abrupt deceleration as might otherwise be experienced upon the shifting operation during vehicle acceleration.
2. Description of the Prior Art
In recent years, automatic transmissions have been used widely in vehicles. Automatic transmissions have their shifting operation controlled by detecting the running speed of the vehicle and the depression of an accelerator pedal to select the optimum speed change from the relationship inbetween. A clutch for connecting an engine and the transmission is disengaged before and engaged after the shifting operation. Therefore, the automatic shifting operation follows the procedure including declutching, shifting and clutching operations, and the clutch is left unapplied in that procedure so that the drive force of the engine is not transmitted to the drive shaft of the vehicle. This interruption of the transmission of the driving force has been conceded as being unavoidable in the operation of the transmission.
If, however, the shifting operation is conducted during an acceleration while the accelerator pedal being depressed, the clutch is released for the operation so that the driver feels the deceleration of the vehicle. The shocks in the declutching operation further increases the uncomfortable feeling of the driver. These deceleration and declutching shocks are desperately left as they are because it is necessary to release the clutch for the shifting operation.